CNAM Colloquium: Collin Broholm, JHU

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Collin Broholm, Johns Hopkins University

Title: Incommensurate magnetism in heavy fermion systems

Abstract: Neutrons and muons were used to explore CeNiAsO and CeAuSb2. The initial instability of the heavy fermion state yields long-wavelength amplitude-modulated SDWs. Analyzing crystal field excitations, we show CeNiAsO is an easy plane system. There is a lower T transition to a commensurate non-collinear state that may result from bi-quadratic interactions. CeAuSb2 is Ising like and the orthorhombic amplitude modulated state is stable to the lowest T. A B-field applied along c yields an incommensurate 2-Q state. Transport anomalies indicate significant modifications in electronic structure that we discuss considering the new information about spin correlations.

[1] Shan Wu and Guy Marcus are major contributors to this work that was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Material Sciences and Engineering under Grant No. DE-FG02-08ER46544.